如何通过httpclient调用获取内容正文？

Question

我一直在试图弄清楚如何读取httpclient调用的内容,我似乎无法得到它.我得到的响应状态是200,但我无法弄清楚如何获得返回的实际Json,这就是我所需要的!

以下是我的代码:

async Task<string> GetResponseString(string text)
{
    var httpClient = new HttpClient();

    var parameters = new Dictionary<string, string>();
    parameters["text"] = text;
    Task<HttpResponseMessage> response = 
        httpClient.PostAsync(BaseUri, new FormUrlEncodedContent(parameters));

    return await response.Result.Content.ReadAsStringAsync();
}

而我只是从一个方法调用它:

Task<string> result =  GetResponseString(text);

这就是我得到的

response Id = 89, Status = RanToCompletion, Method = "{null}", Result = "StatusCode: 200, ReasonPhrase: 'OK', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:\r\n{\r\n Connection: keep-alive\r\n Date: Mon, 27 Oct 2014 21:56:43 GMT\r\n ETag: \"5a266b16b9dccea99d3e76bf8c1253e0\"\r\n Server: nginx/0.7.65\r\n Content-Length: 125\r\n Content-Type: application/json\r\n}" System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage>

更新:这是我目前的代码,根据Nathan的回复

    async Task<string> GetResponseString(string text)
    {
        var httpClient = new HttpClient();

        var parameters = new Dictionary<string, string>();
        parameters["text"] = text;

        var response = await httpClient.PostAsync(BaseUri, new FormUrlEncodedContent(parameters));
        var contents = await response.Content.ReadAsStringAsync();

        return contents;
    }

我用这种方法称它为....

 string AnalyzeSingle(string text)
    {
        try
        {
            Task<string> result = GetResponseString(text);
            var model = JsonConvert.DeserializeObject<SentimentJsonModel>(result.Result);

            if (Convert.ToInt16(model.pos) == 1)
            {
                _numRetries = 0;
                return "positive";
            }

            if (Convert.ToInt16(model.neg) == 1)
            {
                _numRetries = 0;
                return "negative";
            }

            if (Convert.ToInt16(model.mid) == 1)
            {
                _numRetries = 0;
                return "neutral";
            }

            return "";
        }
        catch (Exception e)
        {
            if (_numRetries > 3)
            {
                LogThis(string.Format("Exception caught [{0}] .... skipping", e.Message));
                _numRetries = 0;
                return "";
            }
            _numRetries++;
            return AnalyzeSingle(text);
        }
    }

并且它一直在运行,它击中了线路 var model = JsonConvert.DeserializeObject<SentimentJsonModel>(result.Result); 一次,它继续前进而没有停在另一个断点处.

它说,当我暂停执行时

Id =无法计算表达式,因为当前方法的代码已经过优化.,Status =无法计算表达式,因为当前方法的代码已经过优化.,Method =无法计算表达式,因为当前方法的代码已经过优化.,Result =无法计算表达式,因为当前方法的代码已经过优化.

..我继续执行,但它只是永远运行.不确定是什么问题

Answer 1

你使用await/async的方式充其量只是很差,并且很难遵循.你是混合await使用Task'1.Result,这仅仅是混乱.但是,看起来您正在查看最终任务结果,而不是内容.

我已经重写了你的函数和函数调用,这应该可以解决你的问题:

async Task<string> GetResponseString(string text)
{
    var httpClient = new HttpClient();

    var parameters = new Dictionary<string, string>();
    parameters["text"] = text;

    var response = await httpClient.PostAsync(BaseUri, new FormUrlEncodedContent(parameters));
    var contents = await response.Content.ReadAsStringAsync();

    return contents;
}

你最后的函数调用:

Task<string> result = GetResponseString(text);
var finalResult = result.Result;

甚至更好:

var finalResult = await GetResponseString(text);

Answer 2

如果您不想使用async,可以添加.Result以强制代码同步执行:

private string GetResponseString(string text)
{
    var httpClient = new HttpClient();

    var parameters = new Dictionary<string, string>();
    parameters["text"] = text;

    var response = httpClient.PostAsync(BaseUri, new FormUrlEncodedContent(parameters)).Result;
    var contents = response.Content.ReadAsStringAsync().Result;

    return contents;
 }